Transition metals in ZnGeP 2 and other II – IV – V 2 compounds

Semiconductors that exhibit room-temperature ferromagnetism are central to the development of semiconductor spintronics. Transition metal (TM)-doped ABC2 are a promising class of such system. These ternary compound semiconductors have two metal sites A and B that can be substituted by the TMs. A site preference for TM incorporation is crucial for a possible explanation of ferromagnetism since dependent on the TM valent state holes or electrons can be released. For low Feand Cr-doped ZnGeP2, our EPR investigations revealed in addition to the well-known native defects the presence of substitutional Fe (3d, S 1⁄4 2) on Zn site, Fe (3d, S 1⁄4 5 2 ) and Cr (3d, S 1⁄4 1) on Ge site. A photo-induced recharging of Fe to Fe is observed. The Cr center exhibits a wellresolved phosphorus ligand hyperfine splitting. For Fe and Fe, the magnetic site inequivalence of each of the both Zn and Ge sites, respectively, has been detected. Moreover, anti-ferromagnetically coupled Mn–MnZn 2+ pairs have been observed in Mn-doped ZnGeP2. r 2006 Elsevier B.V. All rights reserved. PACS: 76.30.Fc; 75.50.Pp; 71.70.Gm; 70.50.+g